The instant invention relates generally to thermal printing devices and more particularly to a thermal label printing device having a printing film saving system wherein the print head is lifted during media advancement so that the print film is not advanced during media advancement, and an associated arrangement for tensioning of the print media during printing and print head lifting operations so that the printing film does not pull upwardly when the print head is lifted.
Currently available thermal transfer printing heads generally comprise a plurality of thermal elements. The heating elements are generally provided on one side of a flat substrate of ceramic or like material along with the requisite electronic circuitry for controlling the activation of the heating elements.
The thermal transfer printing head is typically used in conjunction with a roller platen assembly and ink transfer printing film or ribbon, which carries a thermally transferable printing ink. During printing, a web of material to be printed is oriented between the thermal elements of the printing head and the roller platen of the roller platen assembly such that the printing ribbon is adjacent to the print head and the material to be printed is adjacent to the roller platen. The roller platen and printing head are moved against each other so that the printing ribbon and the material to be printed are pressed against the printing head such that when selected thermal elements of the printing head are heated, ink from the ink transfer printing ribbon is transferred to the surface of the material.
Thermal transfer printers such as these are often used to print adhesive labels wherein the adhesive labels are serially mounted on a continuous web. These label printers typically have a single drive means located downstream of the print head for drawing or pulling the web from the web supply through the print head. As the web is advanced or pulled through the printing device, the heating elements of the print head are selectively energized so that the print head is only selectively operative for printing on the adhesive label portion of the web rather than on the intermediate portions of the web backing. The labels are printed serially as they pass through the print head and are advanced out of the printer wherein they are either wound on a spool for later use or presented for use by an operator. Such label printers have found widespread acceptance in industries wherein a plurality of adhesive labels is printed identically.
However, in other industries where it is desired to repeatedly change the printing on the labels, such as for example in the individual printing of shipping labels, there are drawbacks to using the same type of continuous printing as for the identical label. The primary problem relates to the use of a continuous web with serial labels, the position of the just printed label with regard to the print head immediately after printing, and the proximity of the exit opening in relation to the print head and the drive assembly. Because the labels are serially mounted on the carrier web, the freshly printed label is still positioned near to the print head after printing, and is still within the drive means. While the exit end of the print head is adjacent to the exit opening in the device, the entire label or a portion of this just printed label is still not immediately accessible to the operator for removal from the web. In this case, the first printed label cannot be removed for use until several additional labels have been printed and have thus advanced the first label outwardly far enough to be accessible. Serially printing labels in this manner and allowing several labels to be backed up within the printer can cause errors in matching the labels with packages or other goods upon which the labels are to be placed.
Accordingly, there is a need for a label printer that can effectively function under both scenarios, i.e. serially printing a plurality of identical labels, or individually printing labels one at a time.